In the past, fan fold or Z-fold paper used in impact printers was moved by conventional drive mechanisms such as tractor rollers having pins thereon and operative to move into and out of contact with mating holes at the edges of the paper. Typically, the rotational velocity of these tractor rollers was directly controlled as a function of print speed using conventional closed loop feedback control system techniques. These tractor rollers would normally drive the printed paper along a predefined paper path and through an output feed port and paper shroud into a paper collection tray or bin attached to the printer.
Whereas the above prior art approach was entirely satisfactory for certain types of impact printing applications, it has not been particularly well suited for high speed impact printers and to handle variations in paper size. And in some cases, the above prior art approach has allowed an undesirable build-up of static electrical charge on the paper to the detriment of even and uniform paper stacking and accumulation at the output paper collection tray of the printer. In addition, these prior art paper drive and accumulation systems could not always be suitably adjusted to accommodate for a variety of form thicknesses, and printers employing such paper drive and accumulation systems were sometimes difficult to load and unload. Furthermore, known prior art paper stacking devices generally operate to the detriment of dot matrix print quality.